TARDIS

A TARDIS is a type of Time Lord vehicle capable of moving across space and time. In the context of the the Doctor Who television series, the term is generally used to refer to the Tardis employed by the Doctor.

TARDIS is an acronym for "Time And Relative Dimensions In Space". A TARDIS travels by entering a space-time vortex and emerging at the point in space and time desired by the pilot. A TARDIS typically has a "chameleon circuit" that allows it to blend into the environment where it "lands", taking the outward appearance of some innocuous object for its destination. Because of discoveries in "transdimensional physics", a TARDIS can have substantially greater internal volume than external volume.

The Doctor's TARDIS

The Doctor's TARDIS has the distinctive feature of having a broken chameleon circuit that is stuck in the form of a 20th century British police call box.